§ 270. Official map, establishment. The town board may establish an
official map of that part of the town outside the limits of any
incorporated city or village showing the streets, highways and parks
theretofore laid out, adopted and established by law and drainage
systems may also be shown on such map. Such map shall be final and
conclusive with respect to the location and width of streets and
highways, drainage systems and the location of parks shown thereon.
Such official map is hereby declared to be established to conserve and
protect the public health, safety and general welfare. The clerk of
every town which has established such an official map shall immediately
file a certificate of that fact with the clerk or registrar of the
county in which said town is located.